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Serum Creatinine (with optional 24-hour urine collection for creatinine clearance calculation)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. It helps assess how well your kidneys are filtering blood.

Quick summary

["Kidney function and waste removal depend on this test."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
30146-5
Short code
MuV Ab sp2 Ser Ql
Synonyms
MuV Ab sp2 Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters for Kidney Health

Creatinine levels can indicate how well your kidneys are working. Higher levels may suggest kidney damage or disease, while lower levels could indicate dehydration or muscle loss. This test is often used alongside other measures to monitor kidney function over time.

What to Expect Before the Test

No special preparation is needed for a blood test. You may have a small needle inserted into your arm to draw blood. If your doctor orders a 24-hour urine test, you’ll collect all urine for a full day, starting after the first void.

Common Causes for This Test

Doctors may order this test if you have symptoms like fatigue, swelling, frequent urination, or if you have a history of kidney problems. It’s also used to check kidney function before surgeries, during pregnancy, or after certain medications.

What the Results Mean

Results are compared to a baseline or reference range provided by your healthcare provider. Abnormal results may prompt further testing or adjustments to treatment, such as medications or lifestyle changes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Kidney Function and Beyond

Short name

Creatinine

Frequently asked questions

Will I feel any pain or discomfort?
Most people experience only mild discomfort or a slight pinch during the blood draw. Urine collection for 24 hours may require reminders to stay hydrated and collect all urine, but it’s generally not painful.
Can I eat or drink normally before the test?
For a blood test, you can eat and drink as usual. For a 24-hour urine test, avoid excessive alcohol or diuretics (like caffeine in large amounts) that could affect results. Follow your doctor’s specific instructions.
How long will it take to get my results?
Blood test results are typically available within a few days to a week, depending on lab processing. Urine tests may take longer, sometimes up to 10 days. Follow-up with your doctor to discuss results and next steps.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy